The present invention relates to an image processing apparatus and an image processing method for performing image processing on a color image input to a digital color copying machine for reading a color image from a document and forming a copy image.
To detect a character/line-work portion from a document image input to the above image processing apparatus, the apparatus discriminates whether or not each local image area is an area where characters are written on a white background.
A conventional image processing apparatus discriminates a white background area only through brightness classification or its spatial distribution, independently of an edge portion or halftone-dot portion. This art is disclosed in Jpn. Pat. Appln. KOKAI Publication No. 11-55505.
However, an intermediate brightness occurs at a character contour portion even in an area where characters are written in a white background area and a high brightness or low brightness occurs at the maximum point or minimum point of a halftone dot even in a half-tone image area. Therefore, there is a problem that the discrimination accuracy of a white background area is not improved by only classifying brightnesses in accordance with threshold values.